Process for raising the softening point of hydrocarbon resins



PROCESS FOR RAISING THE SOFTENING POINT OF HYDROCARBON RESINS John F. McKay, Jr., Cranford, and Donald F. Koenecke,

Elizabeth, N. J., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Application November 1, 1951,

Serial No. 254,448 14 Claims. (Cl. 260-45.5)

This invention relates to a method for improving the properties of hydrocarbon resins and more particularly relates to a method of improving the softening properties of olefin-diolefin resins without degrading the color.

It is known that hydrocarbon resins can be produced from certain refinery streams containing olefins and diolefins by a variety of methods such as polymerization using aluminum chloride or boron trifiuoride as catalysts. The resins produced, however, have softening points that are too low for certain applications. For use as the binding ingredients in floor tile, for example, it is desirable that hydrocarbon resins have softening points of 105 C. or greater so that the floor tiles made therefrom have good hardness-indentation properties. Most of the resins that are produced from such hydrocarbon streams by Friedel Crafts polymerization have softening points lower than 100 C. Heretofore all attempts to raise the softening points of these resins have seriously degraded the color of the resins. This is undesirable, since light colored resins are premium materials. It has now been discovered that 5-10% or more of the synthetic oily polymers and copolymers of diolefins have a surprisingly beneficial effect on the softening point of hydrocarbon resins Without seriously causing loss of color. By the process of this invention, the usually low softening hydrocarbon resins have their softening points raised so that they become suitable for use in floor tile and other places where high softening point is required.

Hydrocarbon resins to which the present invention is applicable are made from petroleum cracked distillates boiling in the range of about 30 C. to 280 C. or any fraction boiling Within this range. The resins are prepared by treating the distillate with 0.25-2.5% of a Friedel Crafts type catalyst such as aluminum chloride, aluminum bromide, boron trifluoride, and the like or solutions, slurries, or complexes thereof. The reactions are conducted at temperatures in the range of 065 C., and preferably -54" C. Residual catalyst is quenched by suitable methods such as addition of methyl alcohol and subsequent filtration, water and/or caustic washing and the final solution is then stripped of unreacted hydrocarbons and low molecular weight oils by vacuum or steam distillation.

In place of the petroleum cracked distillates, the feed to polymerization may consist of mixtures of a diolefin with an olefin. Sufiicient diolefin must be present and in corporated in the polymer to give a resin instead of an oil or a rubbery material.

The synthetic oils useful for improving the softening point of the above resins in accordance with the present invention are oily polymers or copolymers of butadiene, isoprene, dimethyl butadiene, piperylene, methyl pentadiene or other conjugated diolefins having four to six carbon atoms per molecule. Instead of polymerizing any of the aforesaid diolefins alone, they may be copolymerized in admixtures with each other or in admixtures with minor amounts of ethylenically unsaturated monomers copolymerizable therewith, e. g., with 5 to of styrene, styrenes having alkyl groups substituted on the ring such as para methyl styrene, dimethyl styrene or diethyl styrene, acrylonitrile, methacrylonitrile, methyl CII acrylate, methyl methacrylate, vinyl isobutyl ether, methyl vinyl ketone, and isopropenyl methyl ketone. Such synthetic oils may be advantageously prepared by mass polymerization either in the presence of a hydrocarbon soluble peroxide catalyst such as benzoyl peroxide or cumene hydroperoxide, or in the presence of metallic sodium when the monomers consist of a diolefin or of a diolefin with a styrene compound. Suitable polymerization procedures are illustrated below in Runs A and B. Throughout the present description it will be understood that all proportions are expressed on a weight basis unless otherwise specified.

Run A For example, 100 parts of butadiene-1,3 or of piperyl ene, parts of straight run mineral spirits boiling between l50 and 200 C. (Varsol), 3 parts of t-butyl hydroperoxide pure) and 0.75 parts of diisopropyl xanthogen disulfide are heated in a closed reactor at about to remove the dimer and usually adjusted to 50% nonvolatile matter content. The non-volatile constituent, which is the oily polymer of butadiene or piperylene, has

dale et al., filedon October 29, 1947, which describes alternat ve monomers, catalysts, reaction diluents, polythe various ingredients, suitable ranges of polymerization conditions, etc.

Run B An alternative polymerization method using sodium as catalyst is illustrated as follows: 60 to parts of butadiene-1,3 are copolymerized with 40 to 10 parts of styrene in an essentially inert diluent at temperatures ranging from about 25 to C., or preferably between 40 ditions employed. Accordingly, the diluents employed have a boiling point between -15 and 200 C., the low boiling diluents being useful where it is permissible to keep the reaction pressure suificiently high to maintain theddiluent in liquid condition at the reaction temperature use The preferred diluents used in the polymerization are predominantly paraflinic hydrocarbons such as naphtha having a boiling range between about 90 and C., or straight-run mineral spirits such as Varsol having a boiling range between about and 200 C. Pentane, benzene, cyclohexane and similar inert hydrocarbons are also useful individually or in admixture with each per 100 parts of monomers. In other words, the resulting composition as synthesized normally contains about 20 to 50% of the polymer dissolved in a hydrocarbon solvent. When desired, as for use in the present invention, more concentrated compositions can be produced from the synthesis product by stripping oif excess solvent.

it is also desirable to employ in the polymerization about 10 to 40 parts, preferably 20 to 30 parts, of an ether promoter per 100 parts of monomers. Cyclic diethers of 4 to 8 carbon atoms having an O--COO group, such as dioxane-l,4 and its methyl and ethyl homologues, have been found as particularly effective promoters. Other suitable ether promoters are aliphatic monoor di-ethers of 4 to 8 carbon atoms such as diethyl ether, diethyl ether of ethylene glycol, and diethyl ether of diethylene glycol. Finally, it is also beneficial to use about 5 to 35 weight per cent (based on sodium) of an alcohol such as methanol, isopropanol or n-amyl alcohol, especially where the sodium catalyst particles are relatively coarse.

At the end of the reaction, the sodium catalyst is removed from the reaction product, for example, by addition of glacial acetic acid and removal of the resulting salt by filtration, and reaction diluent, ether and alcohol, if any, are separated to the desired extent by fractional distillation.

The resulting product, being usually a solution of poly meric oil in a suitable hydrocarbon solvent such as solvent naphtha or mineral spirits, is, depending on the amount and type of ether used,a clear, colorless to light yellow oil having a viscosity between poises, preferably 1 to poises at a hydrocarbon such as Varsol.

It will be understood that the described sodium polymerization method of Run B may be varied considerably as by omitting the styrene coreactant', or by adding the styrene only after the polymerization of butadiene monomer had begun; or dioxane may be replaced by 10 to 35 parts of another ether modifier having more than 2 carbon atoms such as methyl ethyl ether, or the modifier may be omitted altogether, especially when it is not essential to obtain a perfectly colorless product. Similarly, isopropanol is not necessary, though aliphatic alcohols of less than 6 carbon atoms generally have the beneficial effect of promoting the reaction when present in amounts ranging from about 2 to 50% based on the weight of sodium catalyst. Alternatively, the copolymerization of Run B may be carried out with a peroxide catalyst according to the method of Run A, and the polymerization of butadiene and piperylene may be carried out with a sodium catalyst according to the process of Run B.

According to the preferred method of carrying out the present invention, the hydrocarbon resin, prepared as described above, is placed in an agitated reactor together with 510% of the desired oily polymer or copolymer, preferably at 97-100% NVM. Oxygen and air are preferably excluded. The temperature is maintained at 240-280 C. until the desired increase in softening point is attained.

It is important that the temperature be maintained between 240 and 280 C. since at lower temperatures no copolymerization takes place and at higher temperatures the resin decomposes to dark colored products. It is also important to maintain the amount of oily polymer or copolymer not below 5% since the color is materially degraded when a less amount of oil is used. When more than 10% is used, gelation occurs, but this is important only if a clear product is desired. For such uses as floor tile, gelled products can be used without difficulty. For such uses, as much as 25% of the oily copolymer of butadiene and styrene can be added.

The following examples will serve to illustrate the mode of operation as'well as the advantages of the present invention, though it will be understood that various other embodiments or modifications not specifically illustrated herein are possible without departing from the spirit or scope of the invention.

Example 1 A hydrocarbon stream consisting of 14% dienes, 42% olefins, and 42% aromatics and saturated hydrocarbons, prepared by steam cracking of a gas oil, was polymerized in the presence of aluminum chloride at a temperature of 25 C. A hydrocarbon resin was obtained in 25% yield having a softening point of 90 C. and a color of 3. The resin was recovered by stripping ofi the unreacted hydrocarbons. Analysis indicated that this resin was of a non-cyclic structure, little or none of the aromatic constituents of the feed having entered the composition.

Example 2 A butadiene-styrene copolymer oil was prepared from the following charge:

Parts Butadiene-1,3 80 Styrene 20 Varsol 200 Dioxane 40 Isopropanol 0.2 Sodium 1.5 Straight run mineral spirits; API gravity, 49.0; Flash,

F.; Boiling Range 33-37 Kauri-Butanol Value K. B. Value n-heptane Dispersed to a particle size of 10 to of an Eppenbach Homo-Mixer.

The polymerization to 200 C.; (Reference Scale: B 25.4 K. B. Value).

50 microns by means Solvent Power,

enzene-100 of this charge was carried out at 50 C. in a 2-liter autoclave provided with a mechanical agitator. hours.

Complete conversion was obtained The catalyst was destroye the resulting crude product and the product was to contain 97% non-volatile matter.

d and removed from finished The resulting product had a viscosity of 2.4 poise at 50% non-volatile matter in Varsol.

Example 3 540 g. of a hydrocarbon resin made by the process of Example 1 and 60 g. of a synthetic oil made according to Example 2 and used at 97% NVM were placed in a flask and heated to 240-250 stirred and blanketed with nitrogen.

C. The reactor contents were After 47 hours on temperature, the resin product was cooled. The modified resin had a softening point of 127 the following formulation:

C. and a color This co-bodied resin was used to make a floor tile with The stock worked well on the hot mixing mill and was sheeted from a cold mill.

The tile was lighter red in color than was a control tile made from a courmaroneindene resin with an equivalent formulation. The following evaluations show that the experimental floor tile passes federal specifications and is equivalent to the control floor tile.

McBurney Hardness, Mils TRoom 1 h Flex l Impact Curl amp. 9. s4" ball, 30 sec-' 1 minute onds Ei rlp arimental Floor 8 18 4% Pass.--. 0

e. Control Floor Tile... 8 18 2 Pass.... 0

1 Empirical test.A $4

by means of a thumb screw. the tile breaks through A high value is desirable.

Example 4 The following data show the tile and d the screw before is a measure of flexibility.

effect of varying the conditions of copolymerizmg the resin of Example 1 with tthe synthetic oily polymer or copolymer of this invend undesirable darkening of the sive decomposition an resin (runs 11 and 12) TABLE I [Post-synthesis treatment of hydrocarbon resins Original Hydro- Tempep carbon Tim f Modified e Run Number Treating Agent I Additive a ti re, Treatment o if" Color 4 Color 11 Butadlene Sty- 250-250 83 3 20 Hrs 3 rene Oil. 26 Hrs 3 43 Hrs 3 66 Hr 3 5% Butadiene Sty- 250-250 83 3 5 Hrs 3 rene Oil. 8 47 Hrs 4 71 Km. 4 2% Butadiene Sty- 250-250 83 3 5 Hrs.. 3 rene Oil. 23 Hrs. 9 47 Hrs. 11 71 Hrs 13 Butadiene Sty- 240-250 81 3 6. 5 Hrs 3 rene Oil. 24 Hrs Butadiene Sty- 240-250 81 3 6.5 Hrs 3 rene Oil. (Gelled) one 240-250 81 3 5 Hrs 87 3 23 Hrs 98 4 47 Hrs 109 8 71 Hrs 113 9 7 10% Butadiene Sty- 280 85 4 3 Hrs 107 3 rene Oil. 24 H 136 4 8 None 280 85 4 24H 1 114 '6 9 10% Butudiene Sty- 200 81 3 18.5 77 L3 rene Oil. 26 H 80 3 71.5 85 3 10--.- -d0 160 90 3 18. H 81 3 26 B1 3 71. 82 3 11-.-. .--do 310 81 4 6.5 117 7 12- None 325 92 3 72 Very dark 13- 5% dehydrated Cas- 240-260 81 3 6.5 81 4 tor Oil. 102 10 14 5% Oiticica Oil 240-250 81 3 g 15 5% Polybutadlene 240-250 83 3 106 It 01]. 113 il 16 5% Polypiperylene 240-250 81 3 89 4. z 17 5% Butadiene Sty- 0.5% Calcium 240-250 83 3 105 3 rene Oil. Naphthenate. 126 10 18 10%, Eolybutadlene 280 84 6 109 6 1 Resins made from steam cracked distillate iractions by AlCls polymerization. 1 Percent based on hydrocarbon resin. 3 All softening points by ring and ball method. I; l g. resin dissolved in 67 cc. xylene and color read 011 Gardner colorimeter scale. Rating of 3 is light amber. 6-8 'is dark am or.

i Styrene 20%, butadiene 80 p. when reduced to N VM with V Cracking occurred.

7 Based on copolymer 0 8 Prepared according to Run B.

The data in Table I show the following:

1. The softening point of a hydrocarbon resin is' increased with no degradation in color by polymerizing with 5 to 10% of butadiene-styrene oily copolymer at 240-280 C. (runs 1, 2, and 7).

2. The rate of increase in softening point tends to level out with time of reaction, i. e., the greatest increase in softening point occurs during the early hours of reaction (runs 1 and 2).

3. The reaction occurs two or C. than it does at 240 C.-250 C. (runs 1 and 7).

4. The increase in softening point of the resin is far greater than that heat treatment of hydrocarbon resin by it resin color (runs 7 and 8).

5. Reacting hydrocarbon resin with less than 5% of butadiene-styrene oily co; olymer oil increases softening point )but degrades color, therefore is undesirable (run 3 6. Reacting hydrocarbon resin with 15% butadiene-styrene oily cop While such gelled resins are cations where clear main to make satisfactory floor tile (run 4).

7. Reacting hydrocarbon resin with butadiene-styrene copolymer oil at 200 C. or lower is inoperable. In such cases, th synthetic copolymer oil merely acts to plasticize the resins (runs 9 and 10).

Reacting hydrocarbon resin with butadiene-styrene oil at 310 C. or higher is inope;able because of excessix times faster at 280 or more olymer results in gelation. not suitable for certain appligs are desired, they may be used copolyrlner oil made according to Example 2 used at 97% non-volatile matter. Viscosity=2.4

uVery low boiling material collected in Dry Ice trap.

9. Hydrocarbon resins cannot be cotable drying oils such 'as dehydrated ca oil for the purposes of this invention degrading resin color (runs 13 and 14).

10. The use of 5% polybutadiene oil or oil as resin co-bodying agents is almost as use of the butadiene-styrene co only slightly degraded (runs 15 11. Addition of naphthenate grades resin color (run 17).

12. The use of 10% polybutadiene bodied with vegesto r oil or oiticiea without seriously polypiperylene effective as the polymer and the color is and 16).

driers to the reaction de- 2,705,703 8 r 3.A process for raising the softenin point of a pecarbon resin obtained by heating a petroleum cracked troleum cracked distillate resins which comprises mixing distillate boiling in the range of about 30 to 280 C. 100 parts of the resin with 5 to 10 parts of an oily copolyin the presence of 0.25 to 2.5% Friedel Crafts type mer of butadiene and styrene prepared by mass polymercatalyst to a temperature of -65 C., which comprises ization and heating the mixture at a temperature between heating to 240-280 C. the said resin and at least 5% 240 and 280 C. in the substantial absence of oxygen. of an oily polymer prepared by heating a conjugated 4. A process for raising the softening point of a pediolefin to temperatures between 25 and 95 C. in the troleum cracked distillate resins which comprises mixing presence of 1.5% to 5% of sodium. 100 parts of the resin with 5 to parts of an oily polymer 10. Process according to claim 9 in which the diolefin of butadiene prepared by mass polymerization and heat- 10 is butadiene. ing the mixture at a temperature between 240 and 280 11. Process according to claim 10 in which 20% of C. in the substantial absence of oxygen. the butadiene is replaced by styrene.-

5. A process for raising the softening point of a pe- 12. Process according to claim 9 in which the diolefin troleum cracked distillate resins which comprises mixing is piperylene. 100 parts of the resin with 5 to 10 parts of an oily poly- 13. A process for preparing a hydrocarbon resin of mer of piperylene prepared by mass polymerization and high softening point, which comprises heating to 240- heating the mixture at a p a r tw en 240 and 280 C. a petroleum cracked distillate resins and at least 280 C. in the substantial absence of oxygen. 5% of a synthetic oil prepared by polymerization of 6. A process for raising the softening point of a pebutadiene at temperatures of 90 C. in the presence of troleum cracked distillate resins which comprises mixing 3 parts of tertiary butyl hydroperoxide and 0.75 parts 100 parts of the resin with 5 to 10 parts of an oily of diisopropyl xanthogen disulfide.

copolymer of butadiene and styrene having a viscosity 14. A process for preparing a hydrocarbon resin of of about 0.5 to poises and heating the mixture at a high softening point, which comprises heating to 240- temperature between 240 and 280 C. in th S 280 C. a petroleum cracked distillate resins and at least Stantial abs n f oxygen. 25 5% of a synthetic oil prepared by polymerization of 7. A process according to claim 3 wherein the oily piperylene at temperatures of 90 C. in the presence of copolymer is composed of 80% of combined butad en 3 parts of tertiary butyl hydroperoxide and 0.75 parts and 20% of combined styrene. of diisopropyl xanthogen disulfide.

8. A process for preparing a hydrocarbon resin of high sgzftening point, whichkcolmgrisefi heating to 2410 References Cited in the file of this patent 28 a petro eum crac e isti ate resins an at least 5% of a synthetic oil prepared by copolymerization UNITED STATES PATENTS of butadiene and styrene at temperatures between 25 2,252,333 Rothrock Aug. 14, 1941 and 95 C. in the presence of 1.5 to 5% of sodium. 2,380,456 Maier et al. July 31, 1945 9. A process for raising the softening point of a hydro- 

1. A PROCESS FOR RAISING THE SOFTENING POINT OF A PETROLEUM CRACKED DISTILLATE RESINS WHICH COMPRISES MIXING 100 PARTS OF THE RESIN WITH AT LEAST 5 PARTS OF AN OILY DIOLEFIN HYDROCARBON POLYMER AND HEATING THE MIXTURE AT A TEMPERATURE OF BETWEEN 240* AND 280* C. 